Polymer composition comprising a thermoplastic elastomer and a hydrocarbon plasticiser resin

Abstract

The present invention relates to an polymer composition comprising: - at least one block thermoplastic elastomer of formula A-B-A, wherein A is a thermoplastic block comprising α-methylstyrene units and B is a diene elastomer block predominantly comprising diene units; - at least one optionally hydrogenated hydrocarbon plasticiser resin having an aromatic proton content of 40% or less and a number average molar mass (Mn) of 600 g / mol or more - the hydrocarbon plasticiser resin content is within a range from 5 to 70 phr.

Description

[0001] Polymeric composition comprising a thermoplastic elastomer and a plasticizing hydrocarbon resin

[0002] Technical field

[0003] The present invention relates to a rubber composition comprising a thermoplastic block elastomer, comprising a soft diene block and rigid thermoplastic blocks comprising α-methylstyrene units.

[0004] Prior art

[0005] Thermoplastic elastomers (TPE) are elastomers that are of great interest in many fields due to their combined properties, linked on the one hand to the soft elastomeric block and on the other hand to the rigid thermoplastic block. This rigid phase softens at temperatures exceeding the glass transition temperature (Tg) or the melting temperature (Tm) of the thermoplastic block, and regains its rigidity when the temperature returns to temperatures below the Tg. This particularity of TPE implies a very broad application potential.

[0006] Among the most widespread thermoplastic elastomers are styrene block copolymers. The glass transition temperature of polystyrene blocks is around 80°C to 100°C depending on the size of the polystyrene blocks. For certain applications, the value of the glass transition temperature of polystyrene blocks is insufficient. Indeed, this value does not allow the use of these TPEs to be considered for the manufacture of certain objects subject in particular to specific conditions of use where temperatures exceed 100°C. This is why it has been proposed in the past to substitute polystyrene with poly-(a)-methylstyrene, whose glass transition temperature is higher than that of polystyrene, which allows for better thermal resistance of the manufactured object.

[0007] The Applicant has previously developed tire compositions comprising a thermoplastic elastomer. These tires offer a very good compromise between grip and rolling resistance performance.

[0008] It is known to use plasticizers in combination with thermoplastic elastomers to adjust the rigidity of the composition containing them. It is then advantageous to have plasticizers selective for the diene elastomer phase of the thermoplastic elastomer. Indeed, these make it possible to shift the glass transition temperature of the elastomer phase of the thermoplastic elastomer, which elastomer phase conditions the temperature positioning of the adhesion potential of the material, and to adjust the rigidity of the composition, without modifying the glass transition temperature of the thermoplastic phase of the thermoplastic elastomer (which controls the thermal resistance of the material, particularly for high-speed performance).The Applicant proposed in WO2020136194A1 to use liquid polybutadienes with a specific microstructure and a number-average molar mass of more than 1500 g / mol as a plasticizer to enable this selectivity.

[0009] For tire rubber compound developers, the search for offsetting the often contradictory compromises of tire properties is a constant. Thus, it is a constant concern of tire rubber compound developers to find optimized compromises of wear resistance properties and grip properties, contradictory properties, while ensuring good thermal resistance of the material.

[0010] Statement of the invention

[0011] Continuing its efforts in this research, the Applicant has demonstrated that the combination of a triblock styrenic thermoplastic elastomer, comprising a flexible block consisting of a diene elastomer and two rigid side blocks comprising α-methylstyrene units, and a specific plasticizing hydrocarbon resin makes it possible to obtain a selective effect of the plasticizer in the elastomer phase of the thermoplastic elastomer. This selectivity results in an increase in the Tg of the elastomer phase, without modifying the Tg of the thermoplastic phase, which results in a reduction in the rigidity of the triblock without losing the high temperature resistance of the material. This is all the more unexpected since the specific hydrocarbon resin used has a non-zero aromaticity level and therefore has a certain compatibility with the rigid styrenic blocks, on which the resin ultimately has no significant adverse effect.

[0012] This combination of a styrenic thermoplastic elastomer and a specific plasticizing hydrocarbon resin could advantageously be used in a rubber composition for the tire in order to improve grip with a less rigid material, without however degrading the wear resistance due to the maintenance of the rigidity of the thermoplastic blocks, while also maintaining very good thermal resistance.

[0013] Thus, a first subject of the invention is a polymeric composition comprising: at least one thermoplastic elastomer with blocks of formula ABA, in which A is a thermoplastic block comprising α-methylstyrene units and B is a diene elastomer block comprising mainly diene units, at least one plasticizing hydrocarbon resin, optionally hydrogenated, having an aromatic proton content of less than or equal to 40, advantageously less than or equal to 30%, and a number-average molar mass (Mn) greater than or equal to 600 g / mol, advantageously a number-average molar mass (Mn) less than or equal to 3000 g / mol; the content of the plasticizing hydrocarbon resin is within a range from 5 to 70 phr, the maximum resin content in the composition being adapted according to the aromatic proton content of the resin.

[0014] The invention also relates to finished or semi-finished products comprising this polymeric composition and intended for the manufacture of tires, in particular, a tread of a tire comprising such a composition.

[0015] The invention also relates to a tire comprising such a polymeric composition in all or part of its tread.

[0016] Summary of the invention

[0017] The invention, described in more detail below, relates to at least one of the embodiments listed in the following points: 1 - Polymer composition comprising: at least one thermoplastic elastomer with blocks of formula ABA, in which A is a thermoplastic block comprising α-methylstyrene units and B is a diene elastomer block comprising mainly diene units, at least one plasticizing hydrocarbon resin, optionally hydrogenated, having an aromatic proton content of less than or equal to 40, advantageously less than or equal to 30%, and a number-average molar mass (Mn) greater than or equal to 600 g / mol, advantageously a number-average molar mass (Mn) less than or equal to 3000 g / mol, the content of the plasticizing hydrocarbon resin is within a range from 5 to 70 pce;provided that the plasticizing hydrocarbon resin has an aromatic proton content greater than 15%, the resin content in the composition is at most 35 pce and when the plasticizing hydrocarbon resin has an aromatic proton content greater than 20%, then the resin content in the composition is less than 25 pce, when the plasticizing hydrocarbon resin has an aromatic proton content greater than 30%, then the resin content in the composition is less than 15 pce.;

[0018] 2 - Composition according to embodiment 1 in which the thermoplastic blocks A mainly comprise α-methylstyrene units.

[0019] 3- Composition according to any one of the preceding embodiments in which the thermoplastic blocks A comprise styrene units.

[0020] 4 - Composition according to any one of the preceding embodiments in which the thermoplastic blocks A are homopolymers of α-methylstyrene (poly(α-methylstyrene)).

[0021] 5 - Composition according to any one of the preceding embodiments in which the thermoplastic blocks A comprising α-methylstyrene units represent at least 10% by weight relative to the weight of the thermoplastic elastomer.

[0022] 6 - Composition according to any one of the preceding embodiments in which the thermoplastic blocks A comprising a-methylstyrene units represent from 10 to 45% by weight, more preferably from 10% to 40% by weight relative to the weight of the thermoplastic elastomer.

[0023] 7 - Composition according to any one of the preceding embodiments in which the diene elastomer block B further comprises units derived from one or more styrenic monomers.

[0024] 8 - Composition according to any one of the preceding embodiments in which the diene elastomer block B further comprises styrene units.

[0025] 9 - Composition according to any one of the preceding embodiments in which the diene units of the diene elastomer block B comprise butadiene units.

[0026] 10 - Composition according to any one of the preceding embodiments in which the diene elastomer block B mainly comprises butadiene units. 11 - Composition according to any one of the preceding embodiments in which the diene elastomer block B is a polybutadiene block (BR).

[0027] 12 - Composition according to any one of the preceding embodiments in which the thermoplastic elastomer with blocks of formula ABA is a poly(a-methylstyrene) - polybutadiene - poly(a-methylstyrene) copolymer.

[0028] 13 - Composition according to any one of the preceding embodiments in which said plasticizing hydrocarbon resin has a Tg (glass transition temperature) greater than or equal to 30°C.

[0029] 14 - Composition according to any one of the preceding embodiments in which said plasticizing hydrocarbon resin has a Tg (glass transition temperature) in a range from 30°C to 150°C.

[0030] 15 - Composition according to any one of the preceding embodiments in which the Mn of said plasticizing hydrocarbon resin is between 600 and 1500 g / mol.

[0031] 16 - Composition according to any one of the preceding embodiments in which the level of said plasticizing hydrocarbon resin is within a range from 5 to 55 pce.

[0032] 17 - Composition according to any one of the preceding embodiments in which said plasticizing hydrocarbon resin, optionally hydrogenated, has an aromatic proton content within a range from 0 to 15%, and is present at a content within a range from 5 to 55 pce.

[0033] 18 - Composition according to any one of embodiments 1 to 16 in which said plasticizing hydrocarbon resin, optionally hydrogenated, has an aromatic proton content within a range from 0 to 20%, and is present at a content within a range from 5 to 35 pce, preferably from 5 to 27 pce.

[0034] 19.- Composition according to any one of embodiments 1 to 16 in which said plasticizing hydrocarbon resin, optionally hydrogenated, has an aromatic proton content within a range from 0 to 30%, and is present at a content within a range from 5 pce to 20 pce, more preferably from 5 to 15 pce.

[0035] 20.- Composition according to any one of embodiments 1 to 16 in which said plasticizing hydrocarbon resin, optionally hydrogenated, has an aromatic proton content within a range from 0 to 40%, and is present at a content within a range from 5 pce to 15 pce.21 - Composition according to any one of the preceding embodiments comprising at least one compound chosen from non-thermoplastic elastomers, reinforcing fillers chosen from carbon blacks and other reinforcing fillers, organic and inorganic of siliceous type, in particular silica, as well as mixtures of these fillers, elastomer / filler coupling agents, non-reinforcing fillers, processing agents, stabilizers, plasticizers other than the plasticizing hydrocarbon resin defined in any one of the preceding embodiments, pigments, antioxidants, anti-fatigue agents, anti-ozonating waxes, adhesion promoters, reinforcing resins, crosslinking systems based on sulfur and / or peroxide and / or bismaleimides, crosslinking activators comprising zinc monoxide and stearic acid, guanidine derivatives, extending oils, covering agents silica.

[0036] 22 - Finished or semi-finished product intended for the manufacture of tires comprising a composition according to any one of the preceding embodiments.

[0037] 23 - Tire comprising a composition according to any one of embodiments 1 to 21 in all or part of its tread.

[0038] Definitions

[0039] In this document, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by weight.

[0040] On the other hand, any range of values ​​designated by the expression "between a and b" represents the domain within the limits a and b (i.e., excluding the limits a and b), while any range of values ​​designated by the expression "from a to b" means the range of values ​​from a to b (i.e., including the strict limits a and b). By the expression "between a and b" is meant the range of values ​​designated by the expression "from a to b".

[0041] In the present application, by "predominantly" or "majority" in connection with a compound, it is meant that this compound is in the majority among the compounds of the same type in a composition, that is to say that it is the one which represents the largest weight fraction among the compounds of the same type. Thus, a unit derived from a monomer said to be in the majority in a polymer is that representing the largest weight fraction among the units constituting the polymer, relative to the total weight of said polymer. Or again, a component is said to be in the majority in a composition when it represents the largest weight fraction among the components constituting the composition, relative to the total weight of said composition. In a system comprising a single element of a certain type, this is in the majority within the meaning of the present invention.

[0042] In this description, the term "part per cent of elastomer" or "pce" means the part by weight of a constituent per 100 parts by weight of the elastomer(s), i.e. of the total weight of the elastomer(s), whether thermoplastic or non-thermoplastic, of the composition. Thus, a constituent at 60 pce will mean, for example, 60 g of this constituent per 100 g of elastomer.

[0043] Poly(a-methylstyrene) is commonly understood to mean a homopolymer of a-methylstyrene. In this specification, "X units" in elastomers, whether thermoplastic or not, are units derived from the monomer X, polymerized to synthesize the elastomer. Thus, "a-methylstyrene units" are units derived from the monomer a-methylstyrene.

[0044] The carbon-containing compounds mentioned in the description may be of fossil or bio-sourced origin. In the latter case, they may be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of materials already in use, i.e. they may be, partially or totally, derived from a recycling process, or obtained from raw materials themselves derived from a recycling process. This includes, in particular, monomers, polymers, etc.

[0045] Detailed description of the invention

[0046] Thermoplastic elastomer

[0047] The polymeric composition according to the invention comprises at least one thermoplastic elastomer. The thermoplastic elastomer used for implementing the invention is a block copolymer of formula ABA, in which A is a thermoplastic block comprising α-methylstyrene units and B is a diene elastomer block comprising mainly diene units.

[0048] The number-average molecular mass (Mn) of TPE is preferably between 30,000 and 500,000 g / mol, more preferably between 40,000 and 400,000 g / mol. Below the indicated minima, the cohesion between the elastomer chains of the TPE, in particular due to its possible dilution (in the presence of an extender oil), risks being affected; on the other hand, an increase in the operating temperature risks affecting the mechanical properties, in particular the breaking properties, with the consequence of reduced performance "when hot". Furthermore, an excessively high Mn mass can be detrimental to processing. Thus, it has been found that a value in the range of 50,000 to 300,000 g / mol is particularly well suited, in particular to the use of TPE in a tire composition.

[0049] For styrenic TPEs, the number-average molecular weight (Mn) of the TPE elastomer is determined in a known manner, by size exclusion chromatography (SEC). For example, in the case of styrenic thermoplastic elastomers, the sample is first solubilized in tetrahydrofuran at a concentration of approximately 1 g / l; then the solution is filtered through a 0.45 μm porosity filter before injection. The equipment used is a "WATERS alliance" chromatographic chain. The elution solvent is tetrahydrofuran, the flow rate is 0.7 ml / min, the system temperature is 35°C and the analysis time is 90 min. A set of four WATERS columns in series, with the trade names "STYRAGEL" ("HMW7", "HMW6E" and two "HT6E"), is used. The injected volume of the polymer sample solution is 100 μl.The detector is a “WATERS 2410” differential refractometer and its associated software for processing chromatographic data is the “WATERS MILLENIUM” system. The calculated average molar masses are relative to a calibration curve produced with polystyrene standards. The conditions can be adapted by those skilled in the art. The value of the polydispersity index Ip (reminder: Ip = Mw / Mn with Mw being the weight-average molecular mass and Mn being the number-average molecular mass) of the TPE is preferably less than 3; more preferably less than 2 and even more preferably less than 1.5.

[0050] As is known, TPEs have two peaks of glass transition temperature (Tg, measured according to ASTM D3418), the lower temperature being relative to the elastomeric part of the TPE, and the higher temperature being relative to the thermoplastic part of the TPE. Thus, the soft blocks of TPE are defined by a Tg lower than room temperature (25°C), while the rigid blocks have a Tg higher than 100°C.

[0051] In the present application, when referring to the glass transition temperature (Tg) of the TPE, it is the Tg relative to the elastomer block. A Tg value higher than these values ​​may decrease the performance of the composition when used at very low temperatures.

[0052] To be both elastomeric and thermoplastic in nature, the TPE must have sufficiently incompatible blocks (i.e. different due to their respective chemical nature, polarity or Tg) to retain their own properties as elastomeric or thermoplastic blocks.

[0053] The TPEs useful for the purposes of the invention are triblock elastomers of formula ABA with two rigid thermoplastic segments comprising α-methylstyrene units connected by a flexible segment consisting of a diene elastomer.

[0054] Elastomer block

[0055] The elastomer block of the TPE for the purposes of the invention may be any elastomer known to those skilled in the art. They generally have a Tg of less than 0°C and very preferably less than -10°C. A Tg value higher than these values ​​may reduce the performance of the composition when used at very low temperatures. Also preferably, the Tg of the elastomer block of the TPE is greater than -100°C.

[0056] By diene elastomer we mean an elastomer derived at least in part (i.e., a homopolymer or a copolymer) from diene monomers (monomers carrying two carbon-carbon double bonds, conjugated or not).

[0057] According to one embodiment of the invention, by diene elastomer is meant any homopolymer obtained by polymerization of a conjugated diene monomer having 4 to 15 carbon atoms, or any copolymer obtained by copolymerization of one or more conjugated dienes having 4 to 15 carbon atoms between them or with one or more vinylaromatic compounds having from 8 to 20 carbon atoms.

[0058] Suitable conjugated dienes which can be used in accordance with the invention include, in particular, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-di(C1-C5 alkyl)-1,3-butadienes such as, for example, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, phenyl-1,3-butadiene, 1,3-pentadiene and 2,4-hexadiene. Also suitable as conjugated dienes, which can be used in accordance with the invention, are linear terpenes such as, in particular, linear monoterpenes (CioHis), such as myrcene, linear sesquiterpenes (C15H24), such as farnesene, etc.

[0059] According to one embodiment of the invention, the diene elastomer comprises units derived from 1,3-diene monomer having 4 to 12 carbon atoms, more particularly, the diene elastomer comprises units derived from butadiene.

[0060] Suitable vinyl aromatic compounds include styrene, α-methylstyrene, ortho-meta-, para-methylstyrene, the commercial mixture "vinyl-toluene", para-tert-butylstyrene, methoxystyrenes, vinylmesitylene, divinylbenzene and vinylnaphthalene.

[0061] According to one embodiment of the invention, the diene elastomer further comprises units derived from a vinylaromatic monomer, more particularly styrene.

[0062] The diene elastomer is preferably a polybutadiene (BR), a synthetic polyisoprene (IR), a butadiene copolymer, in particular a copolymer of butadiene and a vinyl aromatic monomer, in particular styrene, an isoprene copolymer. According to one embodiment, the diene elastomer is a polybutadiene or a butadiene copolymer.

[0063] The diene elastomer can have any microstructure which depends on the polymerization conditions used.

[0064] Preferably for the invention, the diene elastomer block of the thermoplastic elastomer has a total number-average molar mass ("Mn") of at least 25,000 g / mol, preferably at least 35,000 g / mol and at most 350,000 g / mol, preferably at most 250,000 g / mol, so as to give the thermoplastic elastomers good elastomeric properties and satisfactory mechanical strength. The number-average molar mass of the diene elastomer block of the thermoplastic elastomer can be determined by size exclusion chromatography in a manner known to those skilled in the art using a calibration curve produced from standard dienes.

[0065] Thermoplastic blocks

[0066] The thermoplastic elastomer according to the invention comprises two terminal thermoplastic, or rigid, blocks comprising α-methylstyrene units.

[0067] In the context of the invention, the term thermoplastic block comprising α-methylstyrene units is understood to mean a thermoplastic block comprising units derived from α-methylstyrene and having a glass transition temperature greater than or equal to 100°C, preferably at least 120°C, and preferably at most 200°C, advantageously varying from 100°C to 200°C, preferably from 120°C to 180°C. The Tg of the thermoplastic blocks is measured according to the method described below.

[0068] Preferably, the thermoplastic blocks of the thermoplastic elastomers have a total number-average molar mass ("Mn") of at least 5,000 g / mol, preferably at least 7,000 g / mol, and at most 100,000 g / mol, preferably at most 50,000 g / mol. The number-average molar mass of the thermoplastic block of the thermoplastic elastomer can be determined by size exclusion chromatography in a manner known to those skilled in the art and expressed here relative to polystyrene standards.

[0069] According to preferred embodiments of the invention, the thermoplastic blocks comprising α-methylstyrene units of the thermoplastic elastomer predominantly comprise units derived from α-methylstyrene in order to provide good thermal resistance to the thermoplastic elastomer, as well as to a composition containing it. In other words, according to this embodiment, each thermoplastic block preferably comprises at least 50% by weight, preferably at least 70% by weight, of units derived from the α-methylstyrene monomer.

[0070] When the thermoplastic blocks comprising α-methylstyrene units of the thermoplastic elastomer further comprise units derived from at least one other monomer, the latter may be vinylaromatic, preferably styrene. These units derived from another monomer may also be a conjugated diene.

[0071] According to particularly advantageous embodiments, the thermoplastic blocks of the thermoplastic elastomer are essentially composed of α-methylstyrene units, that is to say that the thermoplastic blocks do not comprise units derived from a monomer other than α-methylstyrene. Thus, better thermal resistance at higher temperatures of the thermoplastic elastomer is observed, as well as of the composition containing it.

[0072] The minimum rate of thermoplastic blocks in thermoplastic elastomers may vary depending on the conditions of use of the thermoplastic elastomers.

[0073] On the other hand, the ability of thermoplastic elastomers to deform during the manufacture of an object can also contribute to determining the proportion of thermoplastic blocks in the thermoplastic elastomers usable according to the invention.

[0074] According to embodiments of the invention, the thermoplastic blocks comprising α-methylstyrene units represent at least 10% by weight relative to the weight of the thermoplastic elastomer, preferably from 10% to 45% by weight, more preferably from 10% to 40% by weight.

[0075] In the context of the invention, the polymeric composition may comprise one or more thermoplastic elastomers having at least one diene elastomer block and at least one thermoplastic block comprising α-methylstyrene units.

[0076] According to preferred embodiments, the TPE is a triblock thermoplastic elastomer which comprises two poly(a-methylstyrene) thermoplastic side blocks and a central diene block, the diene being in particular a homopolymer of a 1,3-diene or a copolymer of a 1,3-diene, the 1,3-diene being as defined above and in particular isoprene or butadiene, preferably butadiene.

[0077] Synthesis

[0078] The thermoplastic elastomer according to the invention can be manufactured in a known manner according to various synthesis methods described in the prior art. One synthesis method consists, for example, in anionically polymerizing α-methylstyrene in order to concomitantly form the two thermoplastic blocks in the presence of polydienyldilithium as a polymerization initiator. For example, WO8505116A1 and EP0014947A1 describe such methods which comprise the copolymerization of styrene and α-methylstyrene to generate the thermoplastic blocks. A triblock copolymer of the poly(α-methylstyrene-co-styrene)-β-polydiene-β-poly(α-methylstyrene-co-styrene) type is thus obtained. Similar synthesis methods can be envisaged for manufacturing poly(a-methylstyrene)-b-polydiene-poly(a-methylstyrene) triblock polymers using polydienyllithium as a polymerization initiator. Such a process is for example described in FR3045615.

[0079] Another method of synthesis consists of anionically polymerizing α-methylstyrene in a first step. Then, in a second step, the diene monomer is polymerized on the living poly(α-methylstyrene) chains obtained. This gives a poly(α-methylstyrene)-b-polydiene diblock polymer whose dienyl end is living. To obtain a triblock thermoplastic elastomer, a coupling agent is added at this stage to couple the dienyl blocks of the chains. This step is carried out in a manner known per se. Coupling agents generally contain a silicon or tin atom, substituted by two groups reactive with respect to the carbanion end of the living polymer chains. Examples of coupling agents include di-halotin and di-halosilane, in particular dibutyltin dichloride or dimethyldichlorosilane, or dialkoxysilanes.The polymer resulting from the coupling step is a poly(a-methylstyrene)-b-polydiene-b-poly(a-methylstyrene) triblock.

[0080] Such synthesis methods are described, for example, in US4302559A. The synthesis of the block copolymer comprises a first step of polymerization of α-methylstyrene at low temperature in the presence of a polar agent. In a second step, a small amount of conjugated diene is added in order to obtain a living polydienyl block to avoid depolymerization of α-methylstyrene. In a third step, in the presence of another polar compound, the addition of conjugated diene monomer makes it possible to insert the residual α-methylstyrene in a random manner. To obtain a triblock copolymer, the polymer resulting from the last polymerization step is coupled using a coupling agent. The central diene elastomer block of the triblock copolymer is, according to this method of synthesis, a poly(butadiene-co-α-methylstyrene) random copolymer.

[0081] Other processes using this second method of synthesizing a poly(a-methylstyrene)-b-polydiene-b-poly(a-methylstyrene) triblock copolymer are described, making it possible to obtain a central diene elastomer block free of a-methylstyrene. For example, in document FR2243214. The process consists, in a first step, of homopolymerizing the a-methylstyrene in a concentrated medium at temperatures between 0°C and 40°C. At the end of this step, the conjugated diene and the solvent necessary for the synthesis of the poly(conjugated diene) block are added. At the end of this last polymerization step, the polymer obtained is coupled using a coupling agent. More recently, W02020070406A1 describes another process for the synthesis of a poly(a-methylstyrene)-b-polydiene-b-poly(a-methylstyrene) triblock copolymer whose central diene elastomer block is also free of a-methylstyrene.

[0082] Those skilled in the art will understand that depending on the method and conditions of synthesis of the thermoplastic elastomer, the product obtained may consist, in addition to the ABA triblock (thermoplastic comprising α-methylstyrene units)-b-diene elastomer-b- (thermoplastic comprising α-methylstyrene units), of other populations of macromolecules such as thermoplastic polymers comprising α-methylstyrene units, diene elastomers or diblock polymers (thermoplastic comprising α-methylstyrene units)-b-diene elastomer. Thus, within the scope of the invention, those skilled in the art will understand that the product of the synthesis comprises all of these populations when the triblock elastomer is not isolated at the end of its synthesis. Therefore, the product resulting from the synthesis may comprise a diblock polymer consisting of a thermoplastic block comprising α-methylstyrene units and a diene elastomer block.Generally then, the product resulting from the synthesis comprises at most 20% by weight of a diblock polymer consisting of a thermoplastic block comprising α-methylstyrene units and a diene elastomer block. In the same way, the product resulting from the synthesis may comprise a thermoplastic polymer comprising α-methylstyrene units.

[0083] Plasticizing hydrocarbon resin

[0084] The applicant surprisingly discovered that among the plasticizing hydrocarbon resins, the resins in accordance with the invention used in association with the thermoplastic elastomer as described above surprisingly made it possible to increase the Tg of the thermoplastic polymer by significantly increasing the Tg of the flexible diene elastomer block, without significantly modifying the Tg of the thermoplastic block. Very advantageously, the modification of the Tg of the thermoplastic block does not exceed 10°C. This demonstrates a selective action of the resin on the flexible block of the thermoplastic elastomer with a view to reducing the rigidity of the thermoplastic elastomer without penalizing the thermal resistance of the material.

[0085] The compositions of the invention comprise a plasticizing hydrocarbon resin, optionally hydrogenated, having a Tg (glass transition temperature) greater than or equal to 40°C, having an aromatic proton level less than or equal to 40, advantageously less than or equal to 30 and a number-average molar mass (Mn) greater than or equal to 600 g / mol.

[0086] In a manner known to those skilled in the art, the term "resin" is reserved in the present application, by definition, for a compound which is on the one hand solid at room temperature (23°C) (as opposed to a liquid plasticizing compound such as an oil), and on the other hand compatible (i.e. miscible at the rate used, typically greater than 5 pce) with the thermoplastic elastomer with which it is mixed.

[0087] Such a plasticizing hydrocarbon resin is composed, for example, of cyclopentadiene homopolymer or copolymer resins (abbreviated CPD), dicyclopentadiene homopolymer or copolymer resins (abbreviated DCPD), terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins and mixtures of these resins. Among the above copolymer resins, mention may be made more particularly of those chosen from the group consisting of (D)CPD / vinylaromatic copolymer resins, (D)CPD / terpene copolymer resins, terpene phenol copolymer resins, (D)CPD / C5 cut copolymer resins, (D)CPD / C9 cut copolymer resins, terpene / vinylaromatic copolymer resins, C5 cut / vinylaromatic copolymer resins, and mixtures of these resins.The term "terpene" herein includes, in a known manner, the monomers a-pinene, beta-pinene and limonene. Suitable vinylaromatic monomers are, for example, styrene, a-methylstyrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, vinyltoluene, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, hydroxystyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, any vinylaromatic monomer derived from a C9 cut (or more generally from a C8 to C10 cut).

[0088] More particularly, mention may be made of resins chosen from the group consisting of terpene homopolymer or copolymer resins, C5 cut / C9 cut copolymer resins, and mixtures of these resins.

[0089] The plasticizing hydrocarbon resin useful for the purposes of the invention may optionally be hydrogenated.

[0090] The aromatic proton content of the plasticizing hydrocarbon resin, optionally hydrogenated, according to the invention is less than or equal to 40, advantageously less than or equal to 30%, preferably from 0 to 40%, preferably from 0 to 30%. According to embodiments, the aromatic proton content of the plasticizing hydrocarbon resin, optionally hydrogenated, is within a range of from 0 to 20%. According to embodiments, the aromatic proton content of the plasticizing hydrocarbon resin, optionally hydrogenated, is within a range of from 0 to 15%, preferably within a range of from 0 to 10%.

[0091] The plasticizing hydrocarbon resins, optionally hydrogenated, are obtained by processes well known to those skilled in the art, such as for example by thermal polymerization (i.e. without polymerization catalyst).

[0092] The plasticizing hydrocarbon resin, optionally hydrogenated, according to the invention has a number-average molar mass (Mn) greater than or equal to 600 g / mol. Preferably, the plasticizing hydrocarbon resin, optionally hydrogenated, has a number-average molecular mass Mn in a range from 600 to 3000 g / mol, preferably from 600 to 1500 g / mol. Beyond this value, the processing of the resin in a mixture with the TPE is degraded and consequently the compatibility with the flexible block of the TPE is less good.

[0093] Preferably, the plasticizing hydrocarbon resin, optionally hydrogenated, has a polymolecularity index Ip less than or equal to 2, preferably less than or equal to 1.8, preferably less than 1.7.

[0094] Preferably, the plasticizing hydrocarbon resin, optionally hydrogenated, according to the present invention has a glass transition temperature Tg greater than or equal to 30°C, preferably within a range from 30°C to 150°C, more preferably within a range from 40°C to 150°C.

[0095] According to embodiments, the plasticizing hydrocarbon resin according to the invention, optionally hydrogenated, has a Tg in a range from 30°C to 150°C, as well as a number-average molecular weight Mn in a range from 600 to 3000 g / mol and an aromatic proton content in a range from 0 to 40%. According to embodiments, the plasticizing hydrocarbon resin according to the invention, optionally hydrogenated, has a Tg in a range from 30°C to 150°C, as well as a number-average molecular weight Mn in a range from 600 to 1500 g / mol, and an aromatic proton content in a range from 0 to 30%.

[0096] According to embodiments, the content of plasticizing hydrocarbon resin, optionally hydrogenated, is within a range from 5 phr to 70 phr, preferably from 5 to 55 phr. Indeed, below 5 phr of the plasticizing hydrocarbon resin useful for the purposes of the invention, the effect of the resin would not be sufficient and the thermoplastic elastomer could have too low a Tg shift, while above 70 phr, the composition could have losses in breaking properties and losses of elasticity.

[0097] According to certain advantageous embodiments of the invention, when the plasticizing hydrocarbon resin, optionally hydrogenated, has an aromatic proton content within a range from 0 to 15%, the content of this hydrocarbon resin is within a range from 5 to 70 pce, preferably from 5 to 55 pce.

[0098] According to other advantageous embodiments of the invention, when the plasticizing hydrocarbon resin, optionally hydrogenated, has an aromatic proton content in a range from 0 to 20%, the content of this hydrocarbon resin is in a range from 5 phr to less than 45 phr, preferably from 5 to 35 phr, more preferably from 5 to 27 phr. According to other equally advantageous embodiments of the invention, when the plasticizing hydrocarbon resin, optionally hydrogenated, has an aromatic proton content in a range from 0 to 30%, the content of this hydrocarbon resin is in a range from 5 phr to less than 25 phr, preferably from 5 phr to 20 phr, more preferably from 5 to 15 phr.

[0099] According to other equally advantageous embodiments of the invention, when the plasticizing hydrocarbon resin, optionally hydrogenated, has an aromatic proton content within a range from 0 to 40%, the content of this hydrocarbon resin is within a range from 5 pce to less than 15 pce.

[0100] In other words, when the plasticizing hydrocarbon resin has an aromatic proton content greater than 15%, then the resin content in the composition is less than 45 pce, advantageously at most 35 pce, more advantageously at most 27 pce. The resin content in the composition is at least 5 pce. When the plasticizing hydrocarbon resin has an aromatic proton content greater than 20%, then the resin content in the composition is less than 25 pce, advantageously at most 20 pce, more advantageously at most 15 pce. The resin content in the composition is at least 5 pce. When the plasticizing hydrocarbon resin has an aromatic proton content greater than 30%, then the resin content in the composition is less than 15 pce.

[0101] According to these embodiments, the impact on the Tg of the elastomer block is significant for a surprisingly low impact on the Tg of the thermoplastic blocks. The glass transition temperature, the macrostructure (Mn, Mw, Ip) and the aromatic proton content of the plasticizing hydrocarbon resin, optionally hydrogenated, are determined according to the methods described below in the section devoted to examples.

[0102] The plasticizing hydrocarbon resins, optionally hydrogenated, in accordance with the invention are commercially available under the references A125 and S135 from DRT, under the reference NevChem 140 from Neville Chemical, under the references PICCOTAC 8090 and PICCOTAC 9095 from EASTMANN, under the reference Sylvatraxx 6720 from KRATON, under the reference Novarez TK100 from Rain Carbon...

[0103] The table below summarizes the characteristics of the commercial resins in accordance with the invention cited above.

[0104] As already mentioned above, the combination of the thermoplastic elastomer and the specific plasticizing hydrocarbon resin described above can be advantageously used within a rubber composition comprising one or more other components for the manufacture of an object subject to specific conditions of use where temperatures exceed 100°C. Such a combination thus makes it possible to envisage use in numerous fields. In particular, use can be mentioned in the manufacture of various finished or semi-finished rubber-based products such as pipes, belts, vehicle tires, shoe soles, surgical articles, etc., or semi-finished products for these products.

[0105] Such a finished or semi-finished product is also the subject of the invention. In particular, in view of the particular properties of the polymeric composition of the invention, the latter is particularly suitable for use in manufacturing a finished or semi-finished product intended for tires, particularly in treads, in particular with a view to improving the grip properties while ensuring good thermal resistance of the material, for example for high-speed performance.

[0106] Such a composition is also the subject of the present invention.

[0107] The composition according to the invention may comprise one or more other components usually used in the intended applications. Thus, in the context of an application in the field of tires, the polymeric composition according to the invention may also comprise one or more non-thermoplastic elastomers, such as diene elastomers well known to those skilled in the art.

[0108] According to the invention, the term "diene elastomer" should be understood to mean any synthetic elastomer derived at least in part from diene monomers. More particularly, the term "diene elastomer" means any homopolymer obtained by polymerization of a conjugated diene monomer having 4 to 15 carbon atoms, or any copolymer obtained by copolymerization of one or more conjugated dienes with each other or with one or more vinylaromatic compounds having 8 to 20 carbon atoms.

[0109] Suitable conjugated dienes which can be used in the process according to the invention are, in particular, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C1-C5 alkyl)-1,3-butadiene such as, for example, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, phenyl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene, etc.

[0110] Also suitable as conjugated dienes which can be used in the process according to the invention are linear terpenes such as, in particular, linear monoterpenes (CioHis), such as myrcene, linear sesquiterpenes (C15H24), such as farnesene, etc.

[0111] The diene elastomer possibly present in the composition is preferably chosen from the group of diene elastomers consisting of polybutadienes (BR), synthetic polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers, ethylene and diene copolymers and mixtures of these polymers. Such copolymers are more preferably chosen from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR), isoprene-butadiene-styrene copolymers (SBIR), halogenated or non-halogenated butyl rubbers, and ethylene and butadiene copolymers (EBR).

[0112] According to embodiments of the invention, the polymeric composition comprises the thermoplastic elastomer as the majority elastomer, preferably then the composition comprises at least 50 phr of the thermoplastic elastomer, more preferably at least 70 phr.

[0113] According to other embodiments of the invention, the polymeric composition consists essentially of the thermoplastic elastomer as elastomer. In other words, the rubber composition comprises 100 phr of the thermoplastic elastomer.

[0114] Preferably, the thermoplastic elastomer(s) usable according to the invention and described above are in the majority, in particular are the only elastomers of the polymeric composition for application to tires.

[0115] The composition according to the invention may comprise one or more additives usually present in rubber compositions, particularly intended for vehicle tires.As usual additives, mention may be made, for example, of reinforcing fillers chosen from carbon blacks and other reinforcing fillers, organic and inorganic of siliceous type, in particular silica, as well as mixtures of these fillers, gum / filler coupling agents, non-reinforcing fillers, processing agents, stabilizers, plasticizers other than the plasticizing hydrocarbon resin described above, pigments, antioxidants, anti-fatigue agents, anti-ozonating waxes, adhesion promoters, reinforcing resins, crosslinking systems based on either sulfur and / or peroxide and / or bismaleimides, crosslinking activators comprising zinc monoxide and stearic acid, guanidine derivatives, extension oils, silica covering agents.

[0116] The above-mentioned characteristics of the present invention, as well as others, will be better understood upon reading the following description of several exemplary embodiments of the invention, given for illustrative and non-limiting purposes.

[0117] EXAMPLES OF CARRYING OUT THE INVENTION

[0118] I Tests and measurements:

[0119] A - Measurement of the glass transition temperature Tg of the resins

[0120] All glass transition temperature Tg values ​​are measured in a known manner by DSC (Differential Scanning Calorimetry) according to ASTM D3418 of 1999.

[0121] B - Measurement of the Mn of plasticizing hydrocarbon resins

[0122] The macrostructure (Mw, Mn, Ip and Mz) of the hydrocarbon resin is determined by size exclusion chromatography (SEC) based on ISO 16014 (Determination of average molecular mass and molecular mass distribution of polymers using size exclusion chromatography), ASTM D5296 (Molecular Weight Averages and molecular weight distribution of polystyrene by High performance size exclusion chromatography), and DIN 55672 (size exclusion chromatography).

[0123] For these measurements, the resin sample is solubilized in non-antioxidized tetrahydrofuran to a concentration of 1.5 g / l. The solution is filtered with a 0.45 μm porosity Teflon filter, using for example a disposable syringe fitted with a filter. A volume of 100 μl is injected through a set of size exclusion chromatography columns. The mobile phase is eluted with a flow rate of 1 ml / min. The columns are thermostated in an oven at 35°C. Detection is ensured by a refractometer thermostated at 35°C. The stationary phase of the columns is based on a polystyrene divinylbenzene gel with controlled porosity. The polymer chains are separated according to the size they occupy when solubilized in the solvent: the larger the volume they occupy, the less accessible the pores of the columns are and the shorter their elution time.

[0124] A Moore calibration curve linking the logarithm of the molar mass (logM) to the elution time (te) is previously produced with polystyrene standards, and modeled by a polynomial of order 3: Log (molar mass of polystyrene) = a + b te + c te2 + d te3.

[0125] For the calibration curve, polystyrene standards with narrow molecular distributions (polydispersity index, Ip, less than or equal to 1.1) are used. The molar mass range of these standards extends from 160 to approximately 70,000 g / mol. These standards can be grouped into "families" of 4 or 5 standards with an increment of approximately 0.55 in logM between each.

[0126] Certified standard kits (ISO 13885 and DIN 55672) can be used, such as the vial kits from PSS (polymer standard service, reference PSS-pskitrll-3), as well as an additional PS standard of Mp = 162 g / mol (Interchim, reference 178952). These kits come in the form of 3 vials, each containing a family of standard polystyrene in suitable quantities:

[0127] Black vial: Mp = 1,220, 4,850, 15,500 and 67,500 g / mol.

[0128] Blue vial: Mp = 376, 3,470, 10,400, 46,000 g / mol,

[0129] Yellow vial: Mp = 266, 1,920, 7,200, 28,000 g / mol,

[0130] PS162: Mp = 162 g / mol,

[0131] The number-average molar masses (Mn), mass-average molar masses (Mw), average mass (Mz), peak mass (Mp) and polydispersity (Ip = Mw / Mn with Mw being the weight-average molecular mass, and Mn being the number-average molecular mass) of the resin being analyzed are calculated from this calibration curve. This is why we speak of molar masses relative to a polystyrene calibration.

[0132] The equipment used for SEC measurement is a liquid chromatography chain, for example the Alliance 2690 chain from WATERS, comprising a pump, a degasser and an injector; a differential refractometer (for example the 2410 refractometer from WATERS), data acquisition and processing software, for example the EMPOWER software from WATERS, a column oven, for example the WATERS “columns Heater Module” and 4 columns connected in series in the following order:

[0133] C - Measurement of the proton rate in a resin

[0134] The aromatic proton rate and the ethylenic proton rate are measured by NMR 1 H. This determination is carried out in relation to all the detected signals. Thus, the results obtained are expressed in % of peak area.

[0135] Samples are solubilized in deuterated chloroform (CDCh) at a rate of approximately 10 mg of resin in approximately 1 mL of solvent. Spectra are acquired on a Bruker Avance 500 MHz spectrometer equipped with a Bruker BBO z-grad 5 mm broadband probe. The NMR experiment 1 H uses a single 30° pulse sequence and a 5-second repetition delay between each acquisition. 64 accumulations are performed at room temperature. Chemical shifts are calibrated relative to the protonated impurity of deuterated chloroform; 6 ppm 1 H at 7.20 ppm. The NMR signals 1H of aromatic protons are located between 8.5 ppm and 6.2 ppm. Ethylene protons generate signals between 6.2 ppm and 4.5 ppm. Finally, the signals corresponding to aliphatic protons are located between 4.5 ppm and 0 ppm. The areas of each proton category are related to the sum of these areas to give a distribution in % of area of ​​each proton category.

[0136] D - Differential scanning calorimetry (DSC) of thermoplastic elastomer:

[0137] The characterization of the Tg of the elastomer block and the thermoplastic blocks is carried out by a DSC measurement (DSC1 device from Mettler Toledo). The device is operated under a helium atmosphere. A sample of 10 to 20 mg of thermoplastic elastomer is placed in a hollow conventionally used by those skilled in the art to carry out Tg measurements.

[0138] The sample is first placed in an isothermal state at +25°C for 2 minutes and then cooled to -150°C at a rate of 50°C per minute. An isothermal state is then applied at -150°C for 10 minutes. An initial heating then begins from -150°C to +10°C at a rate of 20°C per minute and continues from 10°C to 250°C at a rate of 50°C per minute. The sample is then quenched to reach -150°C at the maximum rate allowed by the device. The sample is then kept in an isothermal state at -150°C for 15 minutes. The second heating then begins from -150°C to +10°C at a speed of 20°C per minute (Tg measurement range of the elastomer part of the TPE) and continues from +10°C to +250°C at a speed of 50°C per minute (Tg measurement range of the polyalphamethylstyrene blocks). In this measurement only the second heating is used.

[0139] E - Proton Nuclear Magnetic Resonance (NMR 1 H):

[0140] The determinations of the rates of the different monomer units and their microstructures within the thermoplastic elastomer are carried out by NMR analysis. The spectra are acquired on a 500MHz BRUKER spectrometer equipped with a "Broad Band" BBIz-grad 5mm probe. The NMR experiment 1 Quantitative H uses a simple 30° pulse sequence and a 5-second repetition delay between each acquisition. Samples are solubilized in CDCl3. The integration zones considered for quantification are the spectral signature zones of the monomer units known to those skilled in the art.

[0141] II. Synthesis of polymers and preparation of polymer compositions

[0142] In the following tests we will adopt the following name: poly(a-methylstyrene) = PAMS

[0143] A - Synthesis of a triblock polymer poly(a-methylstyrene)-b-polybutadiene-b-poly(a-methylstyrene):

[0144] In an 80 L reactor, 2.464 kg of methylcyclohexane, 6.998 kg of α-methylstyrene and 0.40 mol of tetrahydrofurfurylethyl ether are introduced. After neutralization of the impurities with n-butyl lithium, 0.175 mol of β-butyl lithium are introduced. After 40 minutes at T = 20 °C, the conversion to α-methylstyrene measured by dry extract is 38%. Analysis of the polymer by size exclusion chromatography shows the presence of a single population: Mn = 13,517 g / mol. The Tg of this PAMS polymer measured by DSC is 145 °C.

[0145] At the end of these 40 minutes at 20°C, 30.4 kg of methylcyclohexane, the impurities of which have been previously neutralized with n-butyl lithium, are introduced into the reactor, then 5.5 kg of butadiene are introduced using a pump at a flow rate of 5 kg / h. The reaction medium is maintained at 60°C. At the end of the 60 minutes requiring the introduction of 5.7 kg of butadiene, the conversion to butadiene at the end of these 60 minutes at 20°C is 94%.

[0146] 0.084 mol of dimethyldichlorosilane are then introduced into the reactor. The reaction medium is maintained at 60 °C for 12 minutes. At the end of this coupling step, a triblock polymer poly(a-methylstyrene)-b-polybutadiene-b-poly(a-methylstyrene) is synthesized.

[0147] The mass content of total poly(a-methylstyrene) chains in the final sample measured by NMR is 29%.

[0148] The Tg DSC of the flexible polybutadiene block -56°C.

[0149] The DSC Tg of the PAMS thermoplastic block of this thermoplastic polymer is 145°C.

[0150] B - Preparation of Polymeric Compositions:

[0151] For each composition, the polymer and the resin are placed in a container with toluene in the proportions of 10% by volume of polymer in toluene, and stirred for a period of 24 hours at room temperature. The solution is then placed for drying under a hood at room temperature for a period of 12 hours, then in a vacuum oven at 70°C for 48 hours. The film obtained is shaped by pressing at a temperature of 180°C for 10 minutes in order to obtain the test pieces necessary for the characterizations.

[0152] Tables 1 and 2 summarize the components of the polymer compositions and their respective levels.

[0153] Table 1

[0154] Table 2

[0155] The characteristics of the resins are shown in Table 3.

[0156] Table 3 C - Results of the measurements carried out

[0157] The Tg of the polybutadiene blocks and PAMS blocks were measured according to the method described above. The results are reported in Table 4 below depending on the resin used and its content in the composition.

[0158] Table 4

[0159] It is thus observed that with plasticizing hydrocarbon resins having the characteristics of an aromatic proton rate less than or equal to 40% and a number-average molar mass (Mn) greater than or equal to 600 g / mol, it is possible, depending on the different polymer compositions, to increase the Tg of the elastomer phase, without however prohibitively modifying the Tg of the thermoplastic phase.

Claims

CLAIMS 1. Polymer composition comprising: at least one thermoplastic elastomer with blocks of formula ABA, in which A is a thermoplastic block comprising α-methylstyrene units and B is a diene elastomer block comprising mainly diene units, at least one plasticizing hydrocarbon resin, optionally hydrogenated, having an aromatic proton content less than or equal to 40% and a number-average molar mass (Mn) greater than or equal to 600 g / mol and less than or equal to 3000 g / mol, the content of the plasticizing hydrocarbon resin is within a range from 5 to 70 pce;provided that the plasticizing hydrocarbon resin has an aromatic proton content greater than 15%, the resin content in the composition is at most 35 pce and when the plasticizing hydrocarbon resin has an aromatic proton content greater than 20%, then the resin content in the composition is less than 25 pce, when the plasticizing hydrocarbon resin has an aromatic proton content greater than 30%, then the resin content in the composition is less than 15 pce.; 2. Composition according to claim 1 in which the thermoplastic blocks A mainly comprise α-methylstyrene units.

3. Composition according to any one of the preceding claims in which the thermoplastic blocks A are homopolymers of α-methylstyrene (poly(α-methylstyrene)).

4. Composition according to any one of the preceding claims in which the thermoplastic blocks A comprising α-methylstyrene units represent at least 10% by weight relative to the weight of the thermoplastic elastomer, preferably from 10 to 45% by weight, more preferably from 10% to 40% by weight.

5. Composition according to any one of the preceding claims in which the diene elastomer block B further comprises units derived from one or more styrenic monomers.

6. Composition according to any one of the preceding claims in which the diene elastomer block B mainly comprises butadiene units, preferably the block B is a polybutadiene block (BR).

7. Composition according to any one of the preceding claims in which said plasticizing hydrocarbon resin has a Tg (glass transition temperature) greater than or equal to 30°C, preferably within a range from 30°C to 150°C.

8. Composition according to any one of the preceding claims in which the Mn of said plasticizing hydrocarbon resin is between 600 and 1500 g / mol.

9. Composition according to any one of the preceding claims in which the level of said plasticizing hydrocarbon resin is within a range from 5 to 55 pce.

10. Composition according to any one of the preceding claims in which said plasticizing hydrocarbon resin, optionally hydrogenated, - has an aromatic proton rate in the range from 0 to 15%, and - is present at a rate ranging from 5 to 55 pce.

11. Composition according to any one of claims 1 to 9 in which said plasticizing hydrocarbon resin, optionally hydrogenated, - has an aromatic proton rate in the range from 0 to 20%, and - is present at a rate ranging from 5 to 35 pce, preferably from 5 to 27 pce.

12. Composition according to any one of claims 1 to 9 in which said plasticizing hydrocarbon resin, optionally hydrogenated, - has an aromatic proton rate in the range from 0 to 30%, and - is present at a rate ranging from 5 pce to 20 pce, preferably from 5 to 15 pce. 13.Composition according to any one of the preceding claims comprising at least one compound chosen from non-thermoplastic elastomers, reinforcing fillers chosen from carbon blacks and other reinforcing fillers, organic and inorganic of siliceous type, in particular silica, as well as mixtures of these fillers, elastomer / filler coupling agents, non-reinforcing fillers, processing agents, stabilizers, plasticizers other than the plasticizing hydrocarbon resin defined in any one of the preceding claims, pigments, antioxidants, anti-fatigue agents, anti-ozonating waxes, adhesion promoters, reinforcing resins, crosslinking systems based on sulfur and / or peroxide and / or bismaleimides, crosslinking activators comprising zinc monoxide and stearic acid, guanidine derivatives, extending oils, silica covering agents.

14. Finished or semi-finished product intended for the manufacture of tires comprising a composition according to any one of the preceding claims.

15. Tire comprising a composition according to any one of claims 1 to 13 in all or part of its tread.

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